The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Current powder delivery systems for additive manufacturing (“AM”) processes such as Selective Laser Sintering (“SLS”), Direct Metal Laser Sintering (“DMLS”), or Diode based Additive Manufacturing use a single type or composition of powder per part. The powder is swept over a lowered part creation zone creating a layer of powder of a specified thickness.
As layer upon layer of material is deposited in a traditional SLS or DMLS system, the part being created grows thicker and thicker. For the first few initial layers of part creation, the heat delivered to melt the material is removed by conduction to the base substrate that the powder is initially deposited on. As the part becomes thicker and thicker, this conduction pathway becomes insufficient at removing the excess heat in the part. As a result, the part begins to rise in temperature. The temperature of the part continues to increase as successive materials layers are melted, until the part eventually reaches a temperature which is just below the melting point of the powder. Accordingly, cooling the part to permit the continued application of material layers typically becomes a significant challenge. Complicating this is the desire to be able to fully complete the manufacture of the part, using the AM manufacturing process, in as short a time as possible.
Also, in traditional SLS or DMLS systems, the powder bed is filled with the powder to be melted, as well as a portion of the powder which is not melted. This can result in the powder bed being required to support significant weight when heavy and/or dense powdered material types are being used.